*{
    margin: 0;
    padding: 0;
    list-style: none;
}
a{
    text-decoration: none;
}
/* 导航栏开始 */
nav{
    width: 100%;
    height: 72px;
    border-bottom: 1px solid #ccc;
}
.nav-cen{
    width: 1366px;
    height: 72px;
    background-color: #fff;
    margin: auto;
    /* background-color: rgb(155, 140, 140); */
}
.nav-cen ul li{
    height: 72px;
    padding: 0 20px;
    line-height: 72px;
    list-style: none;
    display: inline-block;
    color: #545c63;
}
.nav-cen ul li img{
    height: 72px;
    width: auto;
    line-height: 72px;
    vertical-align:bottom;
}
.nav-cen ul li a{
    color: #545c63;
    text-decoration: none;
}
.nav-cen ul li a:hover{
    color: black;
}
.nav-cen ul li>span{
    display: inline-block;
    height: 40px;
    width: 247px;
    line-height: 40px;
    border-radius: 5px;
    margin-left:100px;
    background-color: #f3f5f6;
}
.nav-cen ul li span input{
    display: inline-block;
    height: 22px;
    width: 206px;
    padding: 8px 12px;
    line-height: 40px;
    border: none;
    outline: none;
    background-color: #f3f5f6;
}
.nav-cen ul li>span span {
    display: inline-block;
    height: 22px;
    width: 23px;
    padding: 8px 12px;
    line-height: 7px;
    vertical-align: middle;
    text-align: center;
}
.li-ri{
margin-left: 250px;

}
/* 登录 */
.register_box,#login_box{
position: fixed;
width: 100%;
height: 100%;
z-index: 20;
display: none;
background-color: rgba(12, 12, 12,.8);
}
.register,#login_l{
    position: fixed;
    background: rgb(255, 255, 255);
    width: 384px;
    padding: 20px;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    box-shadow: rgb(28 31 33 / 10%) 0px 12px 24px 0px;
    border-radius: 12px;
    transition: all 0.2s ease 0s;
    text-align: center;
}
.x{
    position: absolute;
    right: 10px;
    top: 20px;
    cursor: pointer;
}
.tab-pane #phone,.tab-pane #phone_l,#password,.tab-pane #phone_2,#password_l,#password_3{
    width: 300px;
    height: 48px;
    padding: 0 10px;
    margin-top: 20px;
    border-radius: 15px;
    background-color: #f2f2f2;
    border: none;
    outline: none;
}
#password2_l,#password2_l,#password3_l{
    width: 210px;
    height: 48px;
    padding: 0 10px;
    border: none;
    background-color: #f2f2f2;
    border-radius: 15px 0 0 15px;
    outline: none;
}
#btn2,#btn3{
    height: 48px;
    padding: 0 10px;
    border: none;
    color: blue;
    background-color: #f2f2f2;
    border-radius: 0 15px 15px 0;
    outline: none;
}
.col-2{
    margin-right: 60px;
}
.col-4{
    margin: 0 20px;
}
.btn,.btn_2,.btn_3{
    width: 300px;
    height: 47px;
    border-radius: 20px;
    margin-top: 30px;
    background-color: rgb(245, 16, 16);
    color: white;
    padding: 11px 32px;

}
.login_btn{
    margin-top: 20px;
}
.other{
    padding: 20px 0;
}
.tab-pane>p{
    padding-top: 20px;
}
.tab-pane>p>span{
    color: #4a86ff;
}

/* 注册模块 */
#login div span{
display: inline-block;
margin-right: 10px;
}
/* 注册模块结束 */
/* 导航栏结束 */

/* 中间板块开始 */
article{
width: 100%;
height: 450px;
/* background-color: rgb(42, 145, 177); */
box-shadow:0 10px 15px rgb(179, 175, 175);
position: relative;
border: 1px solid white;
margin-bottom: 30px;
}

.art_center{
    width: 1152px;
    height: 382px;
    margin: auto;
    margin-top: 30px;
    border-radius: 15px;
    background-color: #39364d;
    box-shadow:0 10px 15px #545c63;
}
/* 侧边导航 */
.art_c-l{
    float: left;
    width: 254px;
    border-radius: 15px 0 0 15px;
    /* background-color: #39364d; */
}
.art_c-l>ul{
    position: relative;
    padding: 16px 5px 16px 20px;
    margin: 0;
}
.art_c-l>ul>li{
    position: relative;
    width: 237px;
    height: 50px;
    line-height: 50px;
    color: white;
}
/* 二级侧边 */
.art_c-l>ul>li>div{
    display: none;
    position: absolute;
    width: 700px;
    height: 183px;
    border-radius: 15px;
    box-shadow: 0 0 10px #545c63;
    background-color: #fff;
    z-index: 100;
    top: -10px;
    left: 235px;
}
.art_c-l>ul>li>div span{
    margin-right: 15px;
    color: #9199a1;
    cursor: pointer;
}
.art_c-l>ul>li>div span:hover{
    border-bottom: 1px solid black;
}
 .art_c-l>ul>li:hover div{
    display: block;
}
/*
.art_c-l>ul>li:nth-child(1):hover div{
    top: -10px;
    display: block;
}
.art_c-l>ul>li:nth-child(2):hover div{
    top: -65px;
    display: block;
}
.art_c-l>ul>li:nth-child(3):hover div{
    top: -115px;
    display: block;
}
.art_c-l>ul>li:nth-child(4):hover div{
    top: -165px;
    display: block;
}
.art_c-l>ul>li:nth-child(5):hover div{
    top: -215px;
    display: block;
}
*/
.art_c-l>ul>li:nth-child(6):hover div{
    top: -55px;
    display: block;
}
.art_c-l>ul>li:nth-child(7):hover div{
    top: -65px;
    display: block;
} 
/* 二级侧边结束 */
.art_c-l>ul>li>span:nth-child(2){
    position: absolute;
    font-size: 2px;
    color: #ccc;
    right: 0;
    top: 17px;
    margin-right: 7px;
}
/* 轮播图 */
.art_c-r{
    border-radius: 0 15px 15px 0;
    float: left;
    width: 898px;
    overflow: hidden;
}
.carousel slide{
    border-radius: 0 15px 15px 0;
float: left;
width: 896px;
height: 381px;
}
.item img{
    border-radius: 0 15px 15px 0;
}
.right{
    border-radius: 0 15px 15px 0;
}
.art_right{
    position: fixed;
    top: 300px;
    right: 0;
    box-shadow: 0 0 20px rgb(179, 175, 175);
    background-color: #fff;
    border-radius:15px 0 0 15px;
}
.art_right>ul>li{
    width: 60px;
    height: 40px;
    text-align: center;
    list-style: none;
}

.art_right>ul>li a{
    display: inline-block;
    text-decoration: none;
    color: rgb(126, 122, 122);
    width: 40px;
    height: 40px;
    line-height: 40px;
    border-bottom: 2px solid rgba(233, 230, 230,.5);
}
.art_botton{
    width: 1152px;
    height: 100px;
    background-color: rgb(42, 145, 177);
    margin: auto;
}
/* 新上好课开始 */
.bannerUnder{    
    width: 1152px;
    margin:30px auto;
}
.nav-tabs li img{
    width: 200px;
    margin-right: 25px;
}
.navcentera>div{
    width: 1152px;
    /* height: 678px; */
    /* margin-bottom: 40px; */
}
.bannerUnder>div .tab-content ul>li{
    width: 270px;
    height: 271px;
    display: inline-block;
    margin:11px 7px;
    border-radius: 15px;
    overflow: hidden;
    background-color: #fff;
    box-shadow: 0 6px 10px 0 rgb(95 101 105 / 15%);
}
.bannerUnder>div .tab-content ul{
    margin-top: 20px;
}
.bannerUnder>div .tab-content ul>li:hover{
    transform: translateY(-10px);
    transition: .5s;
}
.bannerUnder ul>li>a{
    text-decoration: none;
}
.bannerUnder ul>li>a>img{
    width: 270px;
    height: 152px;
}
.bannerUnder ul>li>a>p,h4{
    color: black;
    padding:0 8px ;
}
.bannerUnder ul>li>a>h4{
    color:#9199a1;
}
.bannerUnder ul>li>a>.a{
    color: #545c63;
}
.bannerUnder ul>li>a>.b{
   color: red;
}
/* 新上好课结束 */
/* 慕课专栏 */
.navcentera{
    width: 1152px;
    margin: auto;
    height: 58px;
    margin-top: 20px;
    line-height: 58px;
}
.navcentera img{
    width: 200px;
    height: 40px;
}
.navcentera h2{
    float: left;
}
.navcentera p{
    float: right;
    font-size: 15px;
    margin-right: 20px;
}
.navcentera p a{
    color: #ccc;
}
.bannerUnder .navcentera{
    width: 1152px;
    height: 70px;
    margin: auto;
    /* background-color: rgb(102, 9, 9); */
}
.xspt{
    width: 100%;
    height: 500px;
    background-color: rgb(245, 247, 250);
}
.bannerUnderb{
    width: 1152px;
    margin: auto;
    background-color: rgb(245, 247, 250);
}
.bannerUnderb ul li{
    float: left;
    width: 210px;
    height: 267px;
    margin:10px 8px;
    background-color: #f9fcff;
    border-radius: 5px;
    box-shadow:0 5px  5px #ccc;
}

.bannerUnderb ul li a img{
    width: 147px;
    height: 166px;
    margin-left: 40px;
    margin-top: 15px;
}
.bannerUnderb ul li:hover img{
    transform: scale(110%);
    transition: .5s;
}

.bannerUnderb ul>li>a>.a{
    background-color: #ecf1fd;
    font-size: 13px;
    color: #4e14ee;
    margin-left: 115px;
}
.bannerUnderb ul>li>a>.b{
    color: red;
    text-decoration: none;
}
.bannerUnderb>p>a,.foot_c span a{
    display: inline-block;
    width: 80px;
    height: 80px;
    line-height: 80px;
    color: #545c63;
}
.bannerUnderb>p>a:nth-child(1){
    color: black;
}
/* 慕课专栏结束 */

.foot_c{
    width: 1150px;
    margin: auto;
}